package org.apache.maven.repository.internal;

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

import java.io.File;
import java.util.Collections;
import java.util.HashSet;
import java.util.List;
import java.util.Set;

import org.apache.maven.model.Repository;
import org.apache.maven.model.building.FileModelSource;
import org.apache.maven.model.building.ModelSource;
import org.apache.maven.model.resolution.InvalidRepositoryException;
import org.apache.maven.model.resolution.ModelResolver;
import org.apache.maven.model.resolution.UnresolvableModelException;
import org.eclipse.aether.RepositorySystemSession;
import org.eclipse.aether.RequestTrace;
import org.eclipse.aether.artifact.Artifact;
import org.eclipse.aether.artifact.DefaultArtifact;
import org.eclipse.aether.impl.ArtifactResolver;
import org.eclipse.aether.impl.RemoteRepositoryManager;
import org.eclipse.aether.repository.RemoteRepository;
import org.eclipse.aether.resolution.ArtifactRequest;
import org.eclipse.aether.resolution.ArtifactResolutionException;

/**
 * A model resolver to assist building of dependency POMs. This resolver gives priority to those
 * repositories that have been initially specified and repositories discovered in dependency POMs
 * are recessively merged into the search chain.
 * 
 * @author Benjamin Bentmann
 * @see DefaultArtifactDescriptorReader
 */
class DefaultModelResolver implements ModelResolver {

  private final RepositorySystemSession session;

  private final RequestTrace trace;

  private final String context;

  private List<RemoteRepository> repositories;

  private final ArtifactResolver resolver;

  private final RemoteRepositoryManager remoteRepositoryManager;

  private final Set<String> repositoryIds;

  public DefaultModelResolver(RepositorySystemSession session, RequestTrace trace, String context, ArtifactResolver resolver, RemoteRepositoryManager remoteRepositoryManager, List<RemoteRepository> repositories) {
    this.session = session;
    this.trace = trace;
    this.context = context;
    this.resolver = resolver;
    this.remoteRepositoryManager = remoteRepositoryManager;
    this.repositories = repositories;
    this.repositoryIds = new HashSet<String>();
  }

  private DefaultModelResolver(DefaultModelResolver original) {
    this.session = original.session;
    this.trace = original.trace;
    this.context = original.context;
    this.resolver = original.resolver;
    this.remoteRepositoryManager = original.remoteRepositoryManager;
    this.repositories = original.repositories;
    this.repositoryIds = new HashSet<String>(original.repositoryIds);
  }

  public void addRepository(Repository repository) throws InvalidRepositoryException {
    if (session.isIgnoreArtifactDescriptorRepositories() || !repositoryIds.add(repository.getId())) {
      return;
    }

    List<RemoteRepository> newRepositories = Collections
        .singletonList(ArtifactDescriptorUtils.toRemoteRepository(repository));

    this.repositories = remoteRepositoryManager.aggregateRepositories(session, repositories, newRepositories, true);
  }

  public ModelResolver newCopy() {
    return new DefaultModelResolver(this);
  }

  public ModelSource resolveModel(String groupId, String artifactId, String version) throws UnresolvableModelException {
    Artifact pomArtifact = new DefaultArtifact(groupId, artifactId, "", "pom", version);

    try {
      ArtifactRequest request = new ArtifactRequest(pomArtifact, repositories, context);
      request.setTrace(trace);
      pomArtifact = resolver.resolveArtifact(session, request).getArtifact();
    } catch (ArtifactResolutionException e) {
      throw new UnresolvableModelException(e.getMessage(), groupId, artifactId, version, e);
    }

    File pomFile = pomArtifact.getFile();

    return new FileModelSource(pomFile);
  }

}
